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Light & Light. June 2015: Gene expression factor analysis to differentiate pathways

Bob

Senior Member
Messages
16,455
Location
England (south coast)
Latest gene expression study from co-authors Light & Light. (Alan Light & Kathleen Light.)
Not open access, unfortunately.

Gene expression factor analysis to differentiate pathways linked to fibromyalgia, chronic fatigue syndrome, and depression in a diverse patient sample.
Iacob E Light AR, Donaldson GW, Okifuji A, Hughen RW, White AT, Light KC.
Arthritis Care Res (Hoboken). 2015 Jun 19.
doi: 10.1002/acr.22639.
http://onlinelibrary.wiley.com/doi/10.1002/acr.22639/abstract
http://www.ncbi.nlm.nih.gov/pubmed/26097208

Abstract
OBJECTIVE:
To determine if independent candidate genes can be grouped into meaningful biological factors and if these factors are associated with the diagnosis of chronic fatigue syndrome (CFS) and fibromyalgia (FMS) while controlling for co-morbid depression, sex, and age.

METHODS:
We included leukocyte mRNA gene expression from a total of 261 individuals including healthy controls (n=61), patients with FMS only (n=15), CFS only (n=33), co-morbid CFS and FMS (n=79), and medication-resistant (n=42) or medication-responsive (n=31) depression. We used Exploratory Factor Analysis (EFA) on 34 candidate genes to determine factor scores and regression analysis to examine if these factors were associated with specific diagnoses.

RESULTS:
EFA resulted in four independent factors with minimal overlap of genes between factors explaining 51% of the variance. We labeled these factors by function as: 1) Purinergic and cellular modulators; 2) Neuronal growth and immune function; 3) Nociception and stress mediators; 4) Energy and mitochondrial function. Regression analysis predicting these biological factors using FMS, CFS, depression severity, age, and sex revealed that greater expression in Factors 1 and 3 was positively associated with CFS and negatively associated with depression severity (QIDS score), but not associated with FMS.

CONCLUSION:
Expression of candidate genes can be grouped into meaningful clusters, and CFS and depression are associated with the same 2 clusters but in opposite directions when controlling for co-morbid FMS. Given high co-morbid disease and interrelationships between biomarkers, EFA may help determine patient subgroups in this population based on gene expression.
 
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voner

Senior Member
Messages
592
well, I will note their first limitation to the study they cited:

There are several noteworthy limitations to this study. First, the dataset is cross- sectional and represents only a single timepoint. Previous research has suggested that individuals with CFS expose their biological differences compared to controls following an experimental challenge (16). Therefore, it is not surprising that individuals at baseline may show fewer differences related to FMS, CFS, and depression compared to controls. It is critical that future studies examine these factors following an experimental challenge or treatment intervention known to induce symptom improvement. Secondly,........

so they are measuring at only one single time point with no exercise challenge, etc.

currently, I think it be difficult to find an "experimental challenge or treatment intervention known to produce symptom improvement".